The present invention relates to a data streaming system that is capable of streaming data via a network such as LAN to cause a server system and a client system to reproduce data, for example, audio contents such as music.
Such a system was put to practical use that the audio data (music collection) collected by the entire family are stored into one server system and then clients systems provided in respective rooms are connected to the server system via the network, whereby each member of the family in each room of the house can hear arbitrarily the audio data stored in the server system.
Non-Patent Literature 1:
“Music Cast Catalog”, (online), August 2002, Yamaha Corporation, (Nov. 11, 2002, Search), on the Internet at yamaha.co.jp/product/av/prd/musiccast/index.
In the above system, each member of the family can hear freely the audio data accumulated in the server system via each of a plurality of client systems in each room. However, such system did not have a broadcast function of sending out the same music to the entire room at the same time at a party, or the like, for example.
Respective clients can receive the audio data that the server system streaming-outputs to the network, and then reproduce such data. In this case, there exists the problems that, since it is difficult for respective client systems to synchronize the reproducing starting timing perfectly and also a reproducing speed of the audio data is varied due to a fluctuation in the oscillation frequency of the clock generator circuit, respective reproduced locations of the music are displaced among respective client systems while the audio data are reproduced.
In order to overcome this displacement, it is considered that absolute times of the clocks in respective client systems are synchronized mutually by incorporating the NTP server (NTP (Network Time Protocol) is a protocol designed to synchronize the clocks of computers over a network) into the network. In this case, there exists the problem that a system configuration becomes complicated to bring about an increase in cost. Further, it is considered that a precision of the clock generator circuit in respective client systems should be improved. In this case, not only a cost of each client system is increased but also it is impossible to perfectly synchronize the progress of the music among respective client systems because there is a limit to improvement of the precision.